Frequently Asked #2 Diesel Fuel Questions

24/7 Travel Stores treats for winter operability in the local weather forecast. If you are going into a colder climate or if you don’t plan to burn this tank of fuel immediately 24/7 Travel Stores advises you to add additional additive of your choice.

Several things can be done to further protect equipment prior to reaching temperatures cold enough to cause operability problems. A short list would be:

• Top off tanks every night to minimize condensation.
• Drain water bottoms at regular PM intervals.
• Monitor water separators continually to watch for excessive moisture build-up.
• Minimize the number of 90° elbows in fuel lines if possible.
• Be aware that cross-over lines are generally a source of moisture collection and can experience ice-related problems quickly.

• #1 Diesel fuel has been used to improve the winter operability of diesel fuel. There are, however, downfalls to this method that are very costly. The use of fuel additives is far more economical and has proven to be more beneficial from a maintenance standpoint.
• #1 Diesel has less paraffin (wax) content than #2 diesel. When blended with #2 Diesel, it simply dilutes the wax content in the fuel but will do nothing for moisture that causes icing in filters and fuel lines. Additives addresses moisture with powerful deicer compounds that act as an antifreeze with entrained water.
• #1 diesel also has less BTU / gallon than #2 Diesel with notably diminished horsepower and MPG / GPH. For example, a 70/30 blend has approximately 3% less BTU / gallon than straight #2 diesel fuel. As a result, about a 3% decrease in MPG and horsepower will occur with a 70/30 blend and as much as a 5-7% decline with a 50/50 blend.

Gelling fuel is caused by wax crystallizing in diesel fuel, clogging fuel filters, fuel lines then solidifying in diesel fuel tanks. In #2 Diesel, wax crystals can grow to diameters of 200-300 microns, which easily restricts fuel flow in 10-micron filters. Many of the active ingredients and additives belong to a family of polymers. These Polymers inhibits wax crystal growth by wrapping a proactive “glove” around wax crystals as they form to restrict their growth to approximately 2 microns. It then acts as a dispersant to keep the wax crystals from attaching to each other. In a 10-micron filter, the modified (2 micron) wax crystals easily flow. As temperatures drop and the system is bombarded with more and more wax, additional fuel additive should be added.

Fuel can contain water as high as 500 parts per million (ppm), but as an industry standard, 50 ppm is considered sufficient to cause problems with icing in fuel lines, filters and elbows. Water paste is designed to find free-standing water in the bottom of fuel tanks and will not determine the extent of a problem with water in the fuel. Entrained water can only be detected accurately by the Karl Fischer method used in a fuel laboratory.

Wax / fuel related issues are easily distinguished by fuel that has solidified in fuel tanks. When fuel is liquid in the fuel tank but the fuel filter or fuel lines are blocked, the usual culprit is moisture / ice. When such icing occurs at the fuel filter or lines, fuel flow is halted at which point wax will solidify in small diameter fuel lines, elbows or exposed fuel filters.

Always introduce the additive prior to the fuel. This is extremely important to insure proper agitation and mixture of the fuel and additive. If you add the additive onto an existing load of fuel it will not mix properly and potentially result in cold weather operability problems. It is necessary to put the additive in bulk or saddle tanks first then add fuel.

It is recommended to additize the fuel when the temperature of the fuel (not ambient of outside temperature) is as warm as possible.

The ambient temperature can be – 30°F but fuel temperature can be 20°F. Unless the fuel must be transported over an extreme distance (and allowed to cool significantly) this should seldom be a stumbling block but merely a point of advisement.

It is recommended that the user follow directions written on the additives label to ensure the correct amount of additive added to fuel.

Cloud Point is the point at which wax begins to crystallize and precipitate out of the fuel. Cold Filter Plugging Point (CFPP) is the temperature at which power units will operate with a 10-micron filter. Cloudy fuel has merely reached cloud point but should not be an operability concern. Be advised, however, that the temperature difference between cloud point and CFPP can be as little as 2°F or as much as 30°F, and the only definite way of knowing is through fuel testing.

24/7 Travel Stores stock additives that are intended to re-liquefy gelled fuel. Please follow label instructions on these products.

• Water separators.
• Cross-over lines.
• Elbows in fuel lines.
• Partially plugged filters.